Make room on my phone to update it

You might need to free up some space on your phone if there isn't
enough room to install a software update. You can make room by using the Zune
software (or Windows Phone app for Mac) to temporarily remove some files from
your phone, such as music, videos, apps, or pictures.

For example, in the Zune software, you can go to
Settings > Phone > Sync
Options to modify what gets synced to your phone, and you can go to
Settings > Phone > Reserved
Space to modify the amount of space that Zune reserves on your phone
for synced content. For more information, see
Sync music,
pictures, and videos.